1. Field of the Invention
This invention relates to a welding control method and a welding control apparatus for automatic welding machines in which a welding gun is successively moved by a robot to a plurality of welding spots on the work object for welding.
2. Description of Relevant Art
In conventional automatic welding machines, welding is done by operating the robot according to a teaching data to successively move the welding gun to welding spots where the welding gun is closed for clamping a work object between the electrode tips at the front ends of the gun arms. In this manner, current is applied to the electrode tips to weld the work object. After the welding is completed for all the welding spots, the welding gun is returned to a standby position and the welded work is removed and another work is set at a predetermined position. Then, the welding gun is moved again to the respective welding spots to repeat the welding process.
In the prior art, when the welding gun is moved to a welding spot and closed according to the teaching data even though a user has forgotten to set a work object in position or there is a missetting of a work object as a positioned deviation thereof, the electrode tips directly hit each other without a work object held therebetween or clamp the work object at other parts other than at the welding spot. Even in such abnormal conditions, the conventional welding machines are simply energized to perform welding, causing damages to the gun and making an undesired hole in the work.